Abstract
IMPORTANCE: Adults with intellectual and developmental disabilities (IDDs) experience relatively high rates of psychiatric conditions; however, national estimates of mental health disparities and barriers to access to care remain limited. OBJECTIVE: To examine the prevalence of anxiety and depression, mental health treatment, and cost-related barriers among adults with IDDs compared with those without functional limitations. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used pooled US National Health Interview Survey data collected from January 1, 2021, to December 31, 2023. The analytic sample included 44 478 adults 18 years or older, representing 134.3 million US adults. Adults with IDDs were identified using Washington Group Short Set criteria, indicating significant difficulty with cognition, communication, or self-care beginning before 22 years of age. The sample included 796 adults with IDDs (weighted population, 2.9 million) and 43 682 adults without functional limitations (weighted population, 131.4 million). Data were analyzed from August 18 to December 18, 2025. EXPOSURE: US National Health Interview Survey. MAIN OUTCOMES AND MEASURES: Outcomes included self-reported diagnoses of anxiety and depression, symptom frequency and severity, psychiatric medication use, receipt of past-year counseling or therapy, and cost-related barriers to mental health care. Weighted prevalence estimates and multivariable logistic regression models were used to examine associations between IDD status and outcomes, adjusting for demographic and socioeconomic covariates. Sensitivity analyses incorporated multiple imputation and propensity score weighting. RESULTS: Among 44 478 adults included in the analysis (estimated 52.8% male; mean [SD] age, 48.6 [16.5] year), the 796 adults with IDDs were younger and more likely to have a lower income and public insurance coverage. Diagnosed anxiety occurred in an estimated 57.2% of adults with IDDs vs 10.6% of adults without limitations (adjusted odds ratio [AOR], 9.41; 95% CI, 7.71-11.49), and diagnosed depression occurred in an estimated 57.1% of adults with IDDs vs 9.9% of adults without limitations (AOR, 9.78; 95% CI, 8.08-11.83). Adults with IDDs also reported more common daily anxiety (50.8% vs 7.9%; AOR, 9.72; 95% CI, 8.08-11.71) and daily depression (25.6% vs 1.4%; AOR, 17.73; 95% CI, 13.84-22.72), use of prescribed medications for anxiety (41.7% vs 8.6%; AOR, 7.02; 95% CI, 5.73-8.60) and depression (38.2% vs 6.0%; AOR, 8.88; 95% CI, 7.28-10.83), and past-year use of counseling or therapy (41.4% vs 9.0%; AOR, 5.83; 95% CI, 4.78-7.11). CONCLUSIONS AND RELEVANCE: In this cross-sectional study, US adults with IDDs experienced substantially higher rates of mental health conditions, treatment use, and cost-related barriers compared with those without functional impairments. These findings highlight critical gaps for accessible, affordable, and disability-informed mental health services and policy reforms to address systemic inequities.